1. Field of the Invention
This invention relates to floating moorages, and more particularly to a system for anchoring a moorage in a body of water which may be relatively deep and which has a level that can vary considerably.
2. Description of the Prior Art
Moorages composed of a large number of interconnected floats are commonly located in relatively shallow bodies of water. These floating moorages are typically rendered laterally immovable by being loosely secured to upstanding piles embedded in the sea floor.
As the population of boaters continuously increases causing more boats to be constructed, additional marinas must be built to accommodate these boats. Natural shallow water locations for these moorages frequently do not exist in various parts of the country, requiring that less suitable alternatives be considered. Furthermore, otherwise acceptable sites are often ruled off-limits for ecological reasons. Frequently, the only alternatives are relatively deep water moorage sites.
Attempts to apply shallow water floating moorage technology utilizing upstanding piles to deep water sites has not met with success. The reason for this is apparent when one examines the effect of transverse forces imposed on an upstanding pile. The ability of a pile to withstand a given rotational moment is a function of the depth of penetration of the pile in the sea floor as well as the characteristics of the sea floor. The moment imparted to the pile is equal to the product of the moment arm and the magnitude of the side load. Clearly, the moment arm of the longer piles required for deep water moorage is significantly greater than the moment arm of the relatively shorter piles which may be used for shallow water moorages. Thus, with acceptable penetration depth and typical sea floor conditions, the moments imparted to relatively long piles by typical side loads is sometimes sufficient to break the pile or dislodge the pile from the sea floor.
Another problem with floating moorages using upstanding piles is their general unattractiveness, whether or not the moorage is at a deep water or shallow water site. The problem is not significant at high tide since only a small portion of pile is exposed. However, at low tide such moorages present an unattractive forest of piling.
An additional problem with the above described moorages occurs in cold climates where ice develops on the surface of the water. Under certain conditions water adhering to the pile freezes at the EBB cycle causing the pile to adhere to the surface ice. When the tide floods, the surface ice withdraws the pile from the sea floor. Although the withdrawal for each tidal change may be relatively slight, the pile never-the-less becomes dislodged after a sufficient number of cycles.
In addition to the above described problems associated with upstanding pile in general, specific problems exist for various types of piling. Wood piling, for example, is difficult to place, particularly in deep water because the buoyant force of the pile tends to force it into a horizontal position. While concrete or steel piles do not exhibit this problem, they contribute their own sets of problems. Concrete piling, for example, are difficult to transport and require larger equipment for handling and installation. The use of steel pile is limited by their susceptibility to corrosion from rust and electrolysis.
An apparent solution to the aforementioned problems resulting from the use of piling is to eliminate the piling altogether and fix the position of the interconnective floats by other means. While anchoring the floats may appear to be a straight forward alternative, conventional anchoring techniques do not always work under the conditions which the marina floats encounter. In particular, marinas cover a large area and thus cannot be anchored, like a vessel, merely by dropping an anchor overboard. Further, a marina must be located in a fixed geographical location because of specific property boundaries and the need to interface with utility lines such as electric, water, telephone, access, etc. Consequently, drifting of the floats must be kept to a minimum. All of the above problems are greatly increased when the floats are to be anchored in deep water or in bodies of water having a widely fluctuating level.